This disclosure relates to measuring minority carrier diffusion lengths.
Small signal ac-surface photovoltage (SPV) measurements of minority carrier diffusion lengths can be used as a diagnostic method for monitoring contamination and micro defects in silicon wafers. It can be used for evaluation of crystal growth, ingot to wafer processing and wafer cleaning. It also can be used in integrated circuit (IC) fabs for monitoring wafer contamination (e.g., iron contamination) during key wafer processing steps and/or for requalification of processing tools after repair or maintenance.